691: Assertion (A) :
Sodium metal is stored under kerosene.
Reason (R):
Metallic sodium melts when exposed to air.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is NOT a correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
692: A person stood alone in a desert on a dark night and wanted to reach his village which was situated 5 km east of the point where he was standing. He had no instruments to find the direction but he located the polestar. The most convenient way now to reach his village is to walk in the
(a) direction facing the polestar
(b) direction opposite to the polestar
(c) direction keeping the polestar to his left
(d) direction keeping the polestar to his right
693: The continental shelf surrounding the Indian Coast is widest off the
(a) Hooghly Coast
(b) Coromandel Coast
(c) Konkan Coast
(d) South Gujarat Coast
694: In the latter half of the year 2008, which one of the following countries pulled out of commonwealth of Independent States?
(A) Georgia
(B) Kazakhstan
(C) Belarus
(D) Azerbaijan
695: Which one of the following elements is essential for the construction of nuclear reactors ?
(a) Cobalt
(b) Nickel
(c) Zirconium
(d) Tungsten